<!DOCTYPE html>
<html lang="en">

<head>
    <meta charset="UTF-8">
    <!-- 开启理想视口 -->
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        * {
            margin: 0;
            padding: 0;
        }

        .box {
            display: flex;
        }

        .left {
            width: 50vw;
            height: 26.667vw;
            background-color: yellowgreen;
        }

        .right {
            width: 50vw;
            height: 26.667vw;
            background-color: tomato;
        }
    </style>
</head>

<body>

    <div class="box">
        <div class="left"></div>
        <div class="right"></div>
    </div>

</body>

</html>